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The development of the automatic transmission goes back to the early years of the 1930s, although the first true automatic transmission (no clutch needed) did not appear in the production line until 1939. His story begins in the Ford Model T, which operated planetary gear with your foot, took part in the drive more than 15 million units out of the assembly line entre1908 and 1927. They also helped the achievements of other companies: Chrysler working on developing hydraulic drive and hydraulic control system for General Motors and its torque converter as most significant.

It was the Hydra-Mastic division of General Motors, formerly the Detroit Transmission Division, which initially completed the first fully automatic transmission-line models in October 1939, six months after they formed this division. Their transmissions were made for Oldsmobile. A year later, Hydra-Mastic transmissions produced about 220 daily, and began shipments to Cadillac. Automatic transmissions are used in some military vehicles during the years of war, and its continued development led to the torque converter, an ingenious drive coupling, hydraulic, which almost did not transmit torque at low vehicle speeds, but at cruising speed was a very efficient hydraulic coupling.
By 1950, all major automakers offered automatic transmissions, and soon after was offered on many models as standard equipment.

So we can say that the main elements of the automatic transmission-fluid coupling, planetary gears and hydraulic control systems, appeared in the last years of the 1940s. Since then, engineers have changed the design, implementation and location of these elements, but have not made major changes or additions to the elements themselves. There have been other developments such as the gearbox controlled by computer, which appeared in the early years of the 1980s, but the same automatic transmission from the driver’s point of view has changed little since 1948.